Emergency lights and exit signs are life-safety equipment, not ordinary decorative luminaires. A successful installation keeps the equipment on the correct power source, preserves battery charging, follows the fixture’s listing and instructions, and ends with a documented functional test. This guide explains the installation sequence and common wiring concepts for commercial LED exit signs, emergency-light units, combo units, and compatible remote heads.
Safety notice: This is a planning and commissioning guide—not a model-specific wiring instruction. De-energize and verify the circuit before work. Hardwired installation should be performed by a qualified person under the adopted electrical/building codes, the authority having jurisdiction (AHJ), and the exact manufacturer instructions supplied with the listed fixture. Conductor colors and connection sequences vary by model.
Before installation: match the fixture to the project
Confirm the location, environment, voltage, mounting method, face count, legend direction, and emergency-lighting coverage before opening the box. A fixture intended for a dry interior ceiling is not automatically suitable for a damp, wet, cold, outdoor, corrosive, or hazardous location. Check the label and product documentation rather than relying on appearance.
- Supply: verify the actual branch-circuit voltage and frequency. Many products accept 120/277 V, but “dual voltage” does not mean both input leads are connected.
- Power behavior: determine whether the sign must remain illuminated continuously and whether the emergency unit requires an unswitched charging feed.
- Mounting: verify wall, ceiling, end, recessed, or pendant mounting and whether a junction box, canopy, or rough-in section is required.
- Environment: match dry, damp, wet, cold, vandal-resistant, hazardous-location, or other ratings to the installed location.
- Emergency capacity: for remote heads, confirm output voltage, polarity, total connected wattage, conductor size, distance, and head compatibility.
For selection help before installation, see the commercial emergency-lighting guide, combo-unit buyer’s guide, and remote-capable emergency-lighting guide.
Tools and documents to have on site
Bring the fixture instructions and submittal, approved drawings, voltage-rated meter or tester, lockout/tagout equipment appropriate to the work, insulated hand tools, listed connectors, approved fasteners, and any required sealants or fittings. For commissioning, have an inspection log and enough time to complete the manufacturer’s initial charge period before the duration test.
Step-by-step installation sequence
1. Confirm placement and mounting orientation
Compare the approved plan with the actual path of egress. Exit-sign legends and directional indicators must be visible from the approach; emergency heads should illuminate the intended floor, stair, change in direction, exit door, or discharge area without creating severe dark gaps. Do not use the fixture body to hide a placement conflict.
2. Identify the correct branch circuit
Emergency equipment usually needs a reliable, continuously available source so its charger can maintain the battery and detect a loss of normal power. A wall switch controlling ordinary room lighting should not inadvertently remove power from the emergency unit. Identify the circuit at the panel and confirm the design intent before disconnecting anything.
3. De-energize, lock out, and verify absence of voltage
Open the upstream disconnecting means, apply the site’s lockout/tagout procedure, and verify the tester on a known source before and after checking the conductors. Never treat a switched-off wall control as electrical isolation. Existing boxes can contain more than one circuit.
4. Prepare the enclosure and support
Use only the knockouts, canopy parts, rough-in components, and mounting holes identified by the manufacturer. Support the fixture from the building structure or an approved box as required; do not leave its weight hanging from conductors. Protect conductors from sharp edges and maintain required enclosure seals.
5. Make the supply connections
Match the measured supply to the fixture label. Connect the specified input lead, neutral where the design requires it, and the equipment grounding conductor or grounding point. Use listed connectors and keep unused leads individually insulated. Do not infer connections solely from a generic color chart.
6. Configure the legend and directional indicators
Install the correct face or stencil, remove only the directional indicator required by the approved egress direction, and close unused openings. For double-face or edge-lit models, confirm that both approaches read correctly before securing the panel. Do not improvise arrows or alter a listed legend assembly.
7. Connect the battery when instructed
Many battery-equipped fixtures ship with the battery disconnected to prevent discharge. The correct moment to connect it varies. Common instructions call for completing AC wiring first, connecting the battery plug, closing the enclosure, restoring AC power, and allowing an initial charge. Follow the supplied sequence; connecting, pinching, reversing, or shorting battery leads can damage the equipment.
8. Install and aim lamp heads
Aim adjustable heads toward the egress surface identified in the lighting plan, not at eye level or into adjacent glass. Tighten them enough to hold alignment without damaging the pivots. Final aiming should be checked under emergency power, because emergency output can differ from normal-lighting conditions.
9. Restore power and check indicators
Close the enclosure, restore branch-circuit power, and observe the charge/status indicator. A dark, flashing, or fault indication may have a model-specific meaning; use the diagnostic table in the fixture instructions. Confirm that the sign legend is properly illuminated and that no conductors, connectors, or battery leads are pinched.
10. Charge and commission
Allow the manufacturer’s stated initial charging period before relying on a full-duration test. Perform the push-button or prescribed functional test, verify emergency heads illuminate and the sign remains in its intended emergency state, then record the fixture ID, location, circuit, date, result, and corrective action. See the monthly and annual testing guide for ongoing inspection procedures.
120/277 V wiring: what “dual voltage” means
A common fixture has separate input leads for different nominal voltages. Only the lead identified for the measured supply is used; the unused voltage lead is capped so it cannot contact another conductor or the enclosure. Some newer fixtures use a universal-voltage input with a different lead arrangement. The nameplate and wiring label control.
| Field condition | Required decision | Do not assume |
|---|---|---|
| 120 V branch circuit | Use the input identified for 120 V | That every black lead is a 120 V input |
| 277 V branch circuit | Use the input identified for 277 V | That orange, red, or another color is universal |
| Universal-voltage fixture | Follow its specific input diagram | That it is wired like a separate-lead model |
| Unknown supply | Measure and trace before connection | That the panel schedule or old fixture is correct |
Switched versus unswitched power
The central question is whether the emergency equipment can continuously monitor normal power and charge its battery. A local switch that removes its charging feed can create a discharged battery or make the unit enter emergency mode during ordinary use. Some engineered systems use listed transfer, bypass, inverter, or control equipment so emergency luminaires can be controlled during normal operation while still illuminating upon loss of normal power. Those designs are not equivalent to simply placing a unit on a wall switch.
Remote-head wiring and load calculations
A remote-capable unit has a specifically rated output for compatible heads. Add the wattage of every connected remote head and any load the instructions require you to include. The total must not exceed the unit’s listed remote capacity. Voltage drop increases with distance, current, and conductor resistance, so use the manufacturer’s conductor and distance table—not a generic rule of thumb.
| Compatibility check | Why it matters |
|---|---|
| Output voltage | A head designed for another voltage may underperform or be damaged. |
| Polarity | Some LED remote heads are polarity sensitive. |
| Total connected load | Overloading can reduce runtime, output, or equipment life. |
| Wire size and distance | Voltage drop can reduce light output at the farthest head. |
| Location rating | Indoor heads are not substitutes for wet, cold, hazardous, or corrosive-location equipment. |
| Listing and manufacturer approval | Electrical similarity alone does not establish compatibility. |
Common installation mistakes
- Feeding the charger through an ordinary wall switch.
- Connecting both voltage-select leads or selecting one without measuring the circuit.
- Leaving the battery disconnected after installation.
- Testing full duration before the initial charge is complete.
- Exceeding remote-head wattage or distance limits.
- Using indoor equipment outdoors or compromising a wet-location seal.
- Removing the wrong directional indicator or reversing an edge-lit panel.
- Aiming heads at walls, ceilings, or occupants instead of the egress surface.
- Failing to label the circuit or record the commissioning result.
Commissioning checklist
- Fixture model, voltage, mounting, and environmental rating match the approved location.
- Branch circuit is identified and intended charging power is continuously available.
- Supply and grounding connections match the fixture label.
- Unused leads are individually insulated; enclosure is closed and sealed.
- Battery is connected in the prescribed sequence.
- Legend, face count, and directional indicators match the egress approach.
- Heads are aimed and remote load remains within the listed capacity.
- Status indicator shows normal operation after power is restored.
- Push-button or prescribed functional test passes after the required charge.
- Fixture location, circuit, date, test result, and responsible person are documented.
Troubleshooting after installation
| Symptom | Checks to make safely |
|---|---|
| No charge/status light | Verify branch-circuit power, correct input lead, neutral where required, connector seating, and model-specific indicator meaning. |
| Emergency heads do not illuminate during test | Confirm initial charge, battery connection, test method, head connection, and fault indication. |
| Short emergency runtime | Confirm full charge, battery age/condition, connected remote load, ambient temperature, and whether the test was started too soon. |
| Remote head is dim | Check compatibility, polarity, conductor size, run length, connector condition, and total load. |
| Unit enters emergency mode unexpectedly | Check for a switched or intermittent AC feed and consult the model’s diagnostic instructions. |
If a battery is confirmed defective, use the exit-sign and emergency-light battery replacement guide. For retrofit power equipment, consult the emergency ballasts and LED drivers guide.
Code, listing, and manufacturer instructions
OSHA requires exit routes to be adequately lighted and exit signs to remain visible and illuminated under its workplace rules. UL Solutions describes UL 924 as the standard for emergency lighting and power equipment. Building, fire, and electrical requirements depend on the adopted editions and local amendments. The AHJ approves the installation, while the product label and supplied instructions define how a specific listed fixture is installed.
Useful primary references:
- OSHA 29 CFR 1910.37 — maintenance, safeguards, and operational features for exit routes
- OSHA Emergency Exit Routes fact sheet
- UL Solutions — emergency lighting testing and certification
- Example manufacturer instructions — Acuity Brands/Lithonia 120/277 V exit sign
Frequently asked questions
Can an exit sign or emergency light be wired to a wall switch?
Not if the switch removes the charging or monitoring power the listed unit requires. Some engineered systems provide normal controls while preserving emergency operation, but they use equipment and wiring designed for that purpose.
Do I connect both the 120 V and 277 V leads?
No. On a separate-lead dual-voltage model, connect only the lead identified for the measured supply and individually cap the unused input. Universal-voltage designs can differ, so follow the fixture label.
When should the battery be connected?
At the point specified by the manufacturer. Many units are wired to AC while de-energized, then have the battery connector joined before AC power is restored, but the exact sequence is model-specific.
Can any remote head be added to any emergency light?
No. The unit must be remote-capable, and the head must match its listed output voltage, polarity, capacity, environmental rating, wiring limits, and manufacturer compatibility requirements.
How soon can the annual duration test be performed?
Only after the manufacturer’s required initial charge period. A quick functional test may be part of commissioning, but an early full-duration test can produce a misleading failure.
Last reviewed August 2026. Codes and product instructions change; verify the adopted requirements and current manufacturer documentation for every project.